Astrology is a chart or map of the heavens, showing planetary positions of a given place date and time. Astrology can also include asteroids and fixed stars. Charts can be time of birth of a person, or the time of an event such as marriage, auction of property, beginning a business, crime and natural disasters. Charts of two people can also be compared as to compatibility and likely problem areas. Birth charts may be progressed to the present day and any time in the future, and may also be compared to the current planets. What the Astrologer does is to calculate the various positions of the planets, also the structure of the chart which includes the rising sign either by computer or by mathematics. Then the chart is ready for interpretation.